Meanwhile, “7th Heaven” vet Barry Watson joins the last season of “Gossip Girl” as a Serena’s (Blake Lively) romantic interest. TVLine reports the actor will recur as a Steven Spence, who is a young entrepreneur.

“Gossip Girl” sixth season debuts Monday, Oct. 8 at 9/8c.

In other casting news,

“Call Me Maybe” singer Carly Rae Jepsen will guest-star on the upcoming season of “90210.” Jepsen will perform in the show’s Season 5 premiere, (Monday, Oct. 8.) reports TVLine.

Liane Balaban will play Sam Winchester’s (Jared Padalecki) new love interest. Balaban will recur as Amelia, a doctor who is described as a “tragedy-damaged soul.” She will later reveal herself as “a brave, sweet, smart, sarcastic woman.”

HBO’s “Boardwalk Empire” and “Treme” season 3 premiere dates were announced earlier today. “Boardwalk Empire” is set to premiere, Sunday, Sept. 16 at 9/8c, while “Treme’s” third season is set to debut Sunday, Sept. 23, at 10/9c.